The present invention relates to systems and methods for delivery of therapeutic or diagnostic agents, wherein the systems provide for varying lengths of the treatment area. The systems and methods herein are designed for selective treating of an area without adversely affecting other parts of the body.
Methods and devices designed to provide drugs to a vessel, include, for example, the use of drug coated balloons, such as disclosed in U.S. Pat. No. 5,954,706 to Sahatjian, for example. Such devices include a catheter with an expandable portion, wherein at least a portion of the exterior surface of the expandable portion is defined by a coating of hydrogel polymer. Incorporated within the hydrogel polymer is a solution of a preselected drug to be delivered to the tissue or plaque. Disadvantages of such devices include the need to choose a particular drug and dosage in advance, as well as limitations on the length and diameter of the treatment area as defined by the predetermined length and diameter of the expandable portion, since these devices often work by direct contact of the device to the vessel.
Another device is disclosed in U.S. Pat. No. 6,287,320 to Slepian. A catheter includes first and second expansile members which are expanded to occlude a diseased region, and a therapeutic agent is introduced into the diseased region via the catheter. The catheter is allowed to remain in place for a therapeutically effective amount of time to allow the therapeutic agent to contact the diseased portion for such a period of time.
Another device is disclosed in US Patent Publication 2007/0078433 to Schwager et al. This device includes a balloon catheter having a predetermined inflow angle of medication. A first and second balloon are positioned on the catheter, with a treatment zone therebetween. Disadvantages of devices such as the ones disclosed in the above-referenced publications include limitations on the length of the treatment area as predetermined by the distance between the expansile members.
A device disclosed in US Patent Application Publication Number 2005/0059930 to Garrison et al. includes a catheter system with at least two expandable occluding elements which are used to create a localized site for administration of agents. The catheters are slidable with respect to one another to vary the space between the balloons as desired. However, the localized site is prone to overpressure since there is no disclosed way to remove excess fluid from the site.
There is thus a need for, and it would be highly advantageous to have, a system and method for localized drug delivery within a vessel, with adjustability of the length of the treatment area and with means for reducing pressure buildup in the treatment zone.